Mary Wilson
Well-known member
Updated 11 June 2024
Applies to England and Scotland
This publication describes the prevalence of the SARS-CoV-2 virus in England and Scotland. SARS-CoV-2 is a coronavirus that causes COVID-19.
Test positivity describes the proportion of lateral flow device (LFD) tests taken by participants in the study that are positive for SARS-CoV-2. However, because tests are imperfect, some tests will return false negative results when an infected individual is tested. A very small number of positive tests may also be false positives when an uninfected individual is tested.
Prevalence is an estimate of the proportion of the population who are infected. It is calculated by adjusting positivity to account for imperfect test performance. This correction is important in this study as LFD tests are used. LFD tests return more false negatives than the polymerase chain reaction (PCR) tests that were used in the previous Office for National Statistics (ONS) Coronavirus (COVID-19) Infection Survey (CIS). Estimates of prevalence are useful for individuals who want to understand their risk of exposure to SARS-CoV-2.
To ensure estimates are representative of the wider population, the prevalence estimates from this cohort are adjusted through reweighting. The reweighting approach used by this study aims to provide an estimate of prevalence that is representative of the whole population in terms of age, geography, and sex. The study only includes participants aged over 2 years and therefore all the analyses conducted, and population projections used in this report do not include individuals aged under 3 years.
In future publications we will include estimates for incidence, the number of new infections each day; and the infection hospitalisation risk, the probability that someone infected with SARS-CoV-2 will require hospital admission. Information on unweighted positivity is available from the ONS Winter CIS publication. ...
https://www.gov.uk/government/stati...l-characteristics-11-january-2024#methodology
Applies to England and Scotland
This publication describes the prevalence of the SARS-CoV-2 virus in England and Scotland. SARS-CoV-2 is a coronavirus that causes COVID-19.
Test positivity describes the proportion of lateral flow device (LFD) tests taken by participants in the study that are positive for SARS-CoV-2. However, because tests are imperfect, some tests will return false negative results when an infected individual is tested. A very small number of positive tests may also be false positives when an uninfected individual is tested.
Prevalence is an estimate of the proportion of the population who are infected. It is calculated by adjusting positivity to account for imperfect test performance. This correction is important in this study as LFD tests are used. LFD tests return more false negatives than the polymerase chain reaction (PCR) tests that were used in the previous Office for National Statistics (ONS) Coronavirus (COVID-19) Infection Survey (CIS). Estimates of prevalence are useful for individuals who want to understand their risk of exposure to SARS-CoV-2.
To ensure estimates are representative of the wider population, the prevalence estimates from this cohort are adjusted through reweighting. The reweighting approach used by this study aims to provide an estimate of prevalence that is representative of the whole population in terms of age, geography, and sex. The study only includes participants aged over 2 years and therefore all the analyses conducted, and population projections used in this report do not include individuals aged under 3 years.
In future publications we will include estimates for incidence, the number of new infections each day; and the infection hospitalisation risk, the probability that someone infected with SARS-CoV-2 will require hospital admission. Information on unweighted positivity is available from the ONS Winter CIS publication. ...
https://www.gov.uk/government/stati...l-characteristics-11-january-2024#methodology